Wrist-pin construction



.Patented- -Ma' 13, 1930 UNITED STA HUGO HEIERMANN, OF FRANKFORT-ON-TH E-MAIN, GERMANY ,wms'r-rmL cons'rnnc'rron I 251,681, and in Germany February 4, 1927.

Application iuea' Februar -3 1923, Serial No.

My invention relates to means for locking pins, bolts andthe like against displacement in their axial direction. Various constructions of locking means have hitherto been 6 proposed with this object in view. They do not, however, fulfil the requirements which are required from such means since known locking means do not permanently ensure the prevention of axial displacement. This drawback is especially noticeable in the. case of the connecting pins or wrist-pins used for pistons since as soon as these pins are capable of being axially displaced, they cause the cylinder wall to be gradually worn out at those places'where the pin moves during the reciprocating movement of the piston.

The object of'the present invention is to provide means which will completely overcome this drawback by constructing the locking means of the pins, bolts or the like in such a manner that the axial displacement thereof will bepermanently prevented.

According to the present invention, this object is attained by constructing the locking means in the formof a narrow spring ring having a wide end surface, which spring ring is inserted in a correspondingly narrow annular groove in such a manner that the said spring ring projects with its end sur- 8 face to such an extent beyond the annular groove that the wide end surface of the ring forms a sure abutment for the bolt, pin or the like which is to be locked in position.

Referring-to the accompanying drawings which illustrate difierent forms ofconstruction of the locking means as applied to two different forms of arrangement for locking the connecting pin of a piston in position.

Figure 1 illustrates in side elevation partly in section, the connecting pin of the pis ton as provided with locking means according to the present invention, 7

' Figure 2 being a transverse section along the line IIII in Figure 1; Figure 3 shows also in side elevation another form of construction of the locking means for the connecting pin of the piston.

Figure 4 being a transverse section along the line IV'-IV of Figure 3;

Figures 5, 6,7 and 8 show different forms of construction of the spring ring by which the connecting pin of the piston is locked in position.

Referrmg which 1s provided 4 is the connecting pin of the piston, pin is loosely mounted in the spring rings which prevent the axial displacement of the connecting pin 3. 5, 5 are to Figures 1 to 4,- 1 is a piston with the bearings 2 and 3.

the bearings 2 and 4'. 6, 6 are annular grooves in which the spring rings 5 of preventing the connecting pin 4. may be provided outer end of each one of the are inserted for'the purpose axial displacementof the The annular grooves 6 as desired either at the two bearings 2 and 3 as shown in Figure 2, or in the two ends of the connecting p ure'4. In the first form 0 connecting pin 4 lies 1n 4 as shown in Figf construction the between the two inner end surfaces of the annular springs 5 so that an axial displacement of the pin 4 relative to the piston 1 is prevented. In the second form of construction, in which the annular springs 5 are sprung 4 they lie against the on 2 and 3, which serve as abutments for the connecting pin 4, thereby preventing its axial displacement.

When the sprlng ring 5 i one of the. annular grooves bearings 2 and 3 ring which springs outwardly,

the annular spring 5 is provided in the use is ma whilst when inserted into a groove provided in the connecting pin 4 use is made I of an elastic ring which As will be seen from springs inwardly. Figures 2 and 4, the

spring ring. 5 is made very thin in order to reduce the surface necting pin 4 as much as p other. hand, the. spring ring from Figures 5 to end or lateral surface, therefor a good seat in of the bearing of the conossible; On the 5 as will be seen formed with a wide in order to provlde and to allow it to. pnoiect beyond the annular groove sufliciently to provide a sufficiently large abutment surface for the connecting pin 4, whereby a lateral displacement thereof is completely prev 7 As will be seen ented.

from Figures 5 to 8, the

s inserted into which into the connecting pin with their inner end surfaces ter end surfaces of the bearlngs de of an elastic the annular groove 6 wide end surface of the ring 5 may be constructed in difleren-t'ways and the ring may be made of a piece of steel having a circular cross-section or from a flat piece of steel.

5 The shape of the ring 5 is such that it possesses sufiicient elasticity, so that when it is inserted into the annular groove 6, it will spring sufliciently far back to become clamped in the said groove. As shown in Fig. 5 for example, the lateral surface of the device tapers towards the free ends thereof. This construction increases the springiness of the device so that it is firmly retainedin the groove in which it is located. The ends of the device are provided with openings,

to enable a tool. to be used for inserting or removing the device from the groove in which it is located.' Each of the bearings may be considered as a sleeve, the pin 4 being turnably'mounted in said sleeves. The end portions of the pin 4 which contact with the inner walls of said sleeves may be defined as the bearing portions. What I claim is: y In combination, a hollow piston having spaced and aligned bearings, a wrist-pin located in said bearings, said wrist-pin being restrained from longitudinal play by spring rings located adjacent the ends thereof and being held against movement relative to said Wrist-pin ina direction parallel to its longitudinal axis, each said spring ring tapering and diminishing in width towards the end portions thereof, said end portions being separate from each other and having enlarged and perforated heads.

Intestimony whereof I aflix my signature.

HUGO HEIERMANN. 

